Accounts Payable

Supplier Inquiries about Unpaid Invoices

Iowa State University seeks to pay invoices promptly. If you have an inquiry about an unpaid invoice, please contact Please provide a purchase order number, invoice number, and an amount when contacting us.

Remedy: Before accepting an order, always get a purchase order number from the Iowa State University employee placing the order. If you have a valid purchase order number but do not put it on your invoice, your payment will be delayed while we attempt to determine the number. If you have a past-due invoice but do not have a valid purchase order number, contact the Iowa State University employee who placed the order and request that he or she provide you with a purchase order number. You will need to email a copy of the invoice, with the purchase order number included, to before payment can be made.

Remedy: All payments require positive approval, either by the Cost Center Manager, or through the Receiving function.

Remedy: Supplier invoices cannot be approved for payment if the buying department disputes the charge. Please contact the Iowa State University employee who purchased the materials. After the dispute is resolved, the Cost Center Manager can approve the supplier invoice for payment.

Remedy: The IRS requires all payments for services to be reported as taxable income. This requires us to request a Taxpayer Identification Number before making payment. If we do not already have a W-9 Form on file for you, your payment will be delayed until we receive one. Although corporations sometimes are exempt from reporting, we require a Form W-9 to recognize the corporation status.

Remedy: If the supplier has not received the check within ten business days after the check was issued, Iowa State University can issue a stop payment on the original check and issue a replacement without charge. Please contact the Office of Compliance at